Crucibles Overview

All crucibles, alumina, magnesia and zirconia to name a few, are manufactured in Capital's own modern purpose-built facility in the Czech Republic where we press, cast and fire various materials into crucibles.

Product Range

Isopressed

Capital Refractories is able to supply a full range of isostatically pressed crucibles from 2 kg capacity to 75 kg, in different grades and qualities. We use a state-of-the-art semi-automated cold isostatic press. Cold isostatic pressing applies pressure to the workpiece in all directions producing products of uniform density. 

The advantages of Isostatically Pressed Crucibles are:

  • Wide range of qualities
  • Wide range of crucibles sizes
  • Smooth internal surface giving a reduction of inclusions
  • Consistent material properties throughout crucible
  • Defect-free - no casting bubbles etc
  • Uniform density throughout the product improving its resistance to thermal stress

Vibrocast

Crucibles are produced by vibration casting (vibrocast) when the required size or shape is uneconomical or impractical by the isopressing production method.

Capital Refractories can offer a range of vibration cast crucibles, including T-Pot Ladles:

Benefits
Complex shapes, e.g. internal pouring siphon

To complement our range of crucibles we also offer numerous ancillary products and materials used within the investment and related foundry industries.

Description

Quality Quality Description
Alumina ..... General purpose crucible with good resistance to acidic and basic slags.
..... AL97I Superior erosion resistance
..... AL88I Improved thermal shock resistance
Chrome Alumina ..... Chrome-enriched crucible has high resistance to slags. Preferred to alumina in more arduous applications
..... CA93I Superior erosion resistance
..... CA84I Improved thermal shock resistance
..... CA91I Specially formulated to withstand the most severe thermal shock applications

Chemistry

Quality Al2O3 SiO2 Fe2O3 Cr2O3
Alumina AL97I 97.5 1.6 <0.1 -
Alumina AL88I 88.5 9.4 0.2 -
Chrome Alumina CA93I 93.4 2.2 <0.1 3.6
Chrome Alumina CA84I 84.3 9.0 0.2 4.8
Chrome Alumina CA91I 91.5 2.2 <0.1 5.3

Properties

Quality Bulk Density / g cm-3 Apparent Porosity / % Thermal Excpansion / x10-6 K-1 Thermal Conductivity / W m-1 K-1 Maximum Service Temperature / °C
Alumina AL97I 2.95 23.8 8.0 4.2 1700
Alumina AL88I 2.59 23.8 8.0 4..2 1700
Chrome Alumina CA93I 3.05 23.0 8.2 3.4 1800
Chrome Alumina CA84I 2.85 20.0 7.6 3.4 1730
Chrome Alumina CA91I 3.10 21.5 8.2 3.4 1800

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